Remote indication apparatus



Aug. 7, 1934. P. H. CRAGO 1,969,359 H REMOTE INDICATION APPARATUS Filed Jan. 25, 1934 (10 Fly 1 L) Fig. 2.

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ZTRE E2712 INVENTOR Paul H.C1 ag0.

BY M M,

H115 A TTORNEY Patented Aug. 7, 1934 UNITED STATES PATET OFFIQEZ 1,969,359 REMOTE INDICATION APPARATUS Application January 25, 1934, Serial No. 708,271

8 Claims.

My invention relates to remote indication apparatus, and has for an object the provision of novel and improved means for continuously indicating at a remote point, such, for example, as a dispatchersomce, the trafiic conditions existing in two sections of a railway track, the different indications being transmitted by direct current over a single line circuit;

One feature of my invention is the provision in of apparatus of this character wherewith conflicting indications may be continuously transmitted over a single pair of line wires by direct current, and which apparatus is so arranged that false indications by what is known as signal flashes are avoided. Other features and advantages of my invention will appear as the specification progresses.

I will describe two forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

' In the accompanying drawing, Fig. 1 is a diagrammatic View showing one form of indication apparatus embodying my invention. Fig. 2 is a View showing a modification of the apparatus of Fig. 1 wherein a single battery in place of a split battery is provided, and which apparatus also embodies my invention.

Similar reference characters refer to similar parts in each of the views.

Referring first to Fig. 1, the reference .characters 1 and l designate the track rails of a stretch of railway track which rails are divided by the usual insulated rail joints to form two track sections 1T and 2T. Each track section 1T and 2T is provided with a track circuit comprising a bat tery 3 and a track relay designated by the reference character R with a prefix corresponding to the section. Although the track sections IT and 2T are here disclosed as being adjacent sections, it will be understood that I do not wish to limit myself to this one arrangement, and these sections may be otherwise disposed with respect to each other should it seem desirable.

Located adjacent the track sections IT and 2T are two relays lAT and 2AT preferably of the direct current neutral type. The relays lAT and 2AT are normally deenergized and are preferably provided with rectifiers' 4 and 5, respectively, which rectifiers are connected across the winding of the associated relay in a direction to snub the winding as the relay is deenergized for causing the relay to be slow releasing in character. Also located adjacent the track sections is a source of direct current here shown as a'battery 6 hav- 55 ing a positive terminal B, a negative terminal N and a central terminal C. That is, the battery 6 is what is commonly known in the signaling art as a split battery. The function of the relays lAT and 2AT and the battery 6 will shortly appear.

Located at a point remote from the track sections IT and 2T, such, for example, as in a dispatchers ofiice, are two indicator lamps lAK and 2AK corresponding respectively to the track sections IT and 2T. These lamps are controlled by relays lAKR and ZAKR, respectively, the circuit for the lamp lAK being easily traced and including a front contact 7 of the relay lAKR, while the lamp 2AK is provided with a similar circuit which includes a front contact 8 of the relay ZAKR. The relays lAKR and ZAKR are preferably direct current neutral relays of the usual type and are provided with a line circuit extending from the ofilce station to the field station and which includes a pair of line wires designated by the reference characters L and Com.

A bridge type rectifier 9 is interposed between the relays lAKR and ZAKR and the line wires L and Com in the following manner. The line wires L and Com are connected with the terminals 10 and. 11 of the rectifier 9, respectively. The winding of the relay lAKR has one terminal connected with the terminal 12 of the rectifier 9 and its opposite terminal connected directly with the line wire Com, while the winding of the relay 2AKR has one terminal connected with the terminal 13 of the rectifier 9 and its other terminal connected with the line wire Com. Asymmetric units of the bridge rectifier'9 are arranged as illustrated in the drawing,-and thus it follows that when the line wire L is positive with respect to the line wire Com, current will fiow from the line wire L through the asymmetric unit in the bridge arm 1012 of the rectifier 9 in its low resistance direction and the winding of the relay lAKR to the line wire Com and that relay will become energized. The asymmetric unit in the arm 11-12 of the rectifier 9 will in this instance act as a snub to the winding of the relay lAKR when that relay is deenergized with the resultthat the relay lAKR is provided with a slow-release characteristic. When the line wire Com is positive with respect to the line wire L, current will fiow through the winding of the relay 2AKR and the asymmetric unit in the bridge arm 1013 in its low resistance direction and that relay will be energized. The asymmetric unit in the bridge arm 1113 will in this instance serve as a snub to the winding of the relay ZAKR when that relay is deenergized with the result that the relay lot 2AKR is provided with a slow-release characteristic.

As shown in Fig. 1, both track sections 1'1 and 2T are unoccupied, both track relays l'IR and 2TB are picked up, no current is supplied to the line circuit and both indicator lamps LAX and ZAK are dark. I shall now assume that a train enters the track section 1T from the left and the track relay lTR, is shunted, the track section 2T remaining unoccupied. With the track relay 1TB. released, current will flow from the B ter-- minal of the battery 6 over a back contact 14 ofthe track relay 1TB, back contact 15 of the relay lAT, line wire L, asymmetric unit of the bridge arm 10-12 of the rectifier 9 in its lot/resistance direction, Winding of relay lAKR and thence by the line wire Com to the C terminal-of the battery 6, and the relay lAliR will be energized, and the indicator lamp lAK will be illuminated to indicats at the dispatchers office the occupancy of the track section 1T. It follows, that as long as the track section 1T is occupied and not the track section 2T, relay lAT remains 'deenerg'ized and current oi positive polarity is continuously supplied to the line circuit and the indicator lAK is continuously displayed. I shall next assume that a'tra'in enters the section 2'? from the right at a time when the track section IT is unoccupied so that the track relay 2TB; is released and the track relay llPu is picked up. With the track relay 2TB released, current will flow from the B terminal of the battery 6 over aback contact 16 of the relay 2TB, back contact 1'? of the relay 2AT,.winding" of the relay lAT and to the C terminal oi the battery 6, and the relay lAT will be held steadily energized. In. response to" the relay lAT' being picked up, current will flow from the C terminahof the cattery 6- 'over the line wire Com, winding of the relay asymmetric unit of the bridge arm lO-'13"of rectifier 9 in its low resistance direction, line wire'L, front contact 18 of relay lATand'to the negative terminal N of the battery dandrelay ZAKR will be energizedto cause the lamp'2AK to be illuminated to indicate at the dispatchers office the'occupancy' of the track section 2T. Consequently-as long as the track section 2')? is occupied'and-not the other section, the relay lA'I ishel'd steadily energized and current of negative polarity is continously supplied .to 'the'line circuit and the indicator ZAK is steadily displayed. 1 shall next assume that both track sections IT and 2T are occupied at the same time sothat both track relays 1TB and ZTR are shunted. Under this condition,

7 current will flow from the B terminal of the loattery 6' over the back-contact 16' of the track relay 2TB, back contact 17 of relay ZAT, wind-ingof relay lAT and to the C batteryte'rm-inal; and the r'elay-lAT will be energized. When the relay IAT picks up, current'will flow from the B terminal of the battery 6' over back contact 14. of the track relay 1TB, a front contact 1-9 of the relay 1AT,.winding of therelay 2AT and theCterminal of battery 6, and that relay will be energized.-

IJ As the'relay ZAT picks up, the circuit to the relay l-AT is opened at the back contact 1'7 and relay LAT is released at the end of its slow-release period, opening the front contact 19 in the circuit to the relay ZAT and that relay is released at the end of its slow-release period, with the result that both relays l-A'I-and 2A1" are now 'de'e'nergized ready to start theoperation over again. It" is clear, therefore, that with both track relays 1TB and 2TH released'the relay lATwill be operated to alternately close the front contact 18' and the -ma-in picked up from the one operation to the next of the relay lAT and, consequently, both indicators lAK and 2AK will be continuously displayed iii-response to the occupancy of both track 'It is clear fror'n' the foregoing description that should the'track section 1T now become vacated,

leaving the track section 2T only occupied, the

trackrelay-lTR will pick up leaving the relay lA T steadily energized over the circuit including the back Contact 16 of the relay 2TB" and theback contact I'T-of the relay 2AT with the result that current of negative polarity will nowbe continuously 'suppliedto the line circuit and only the relay '2AKR' at the office station will be energized, and" only the indicator will 'be'displayed, the indicaton'lAK becoming dark upon the release of the relay lAKR. In the event that both track sections are 'occupiedand the section 2T is'vacat ed previous to thevacatingof the section 1T, the track'relay 2TB; will be picked up, leaving the"'relay lAT without current and that relay will be released with the "result that current of positive polarity will be steadily supplied to the line circuit"and"the relay I'AKR" at the ofii'ce station only will'be'energized; In this instance, the indicator lAK remains displayed while the indicator '2AK'bec0ines dark upon 'ther'elease of the relayZAKR. I

Referring to Fig. 2, asin'gle battery 20 is provid'ed in'place of the split'batte'ry G'ofFig. 1 and the connection of its."termina"ld C with the line wire Com; is'fg'overnedfby the relayIAT. The track relays 1TB and '2TR-of Fig. 2aregovernedby' traffic co'nditi'onsof the two track sections IT and 2T thesameas' in Fig. 1" and these track relays in turn control therel'ays lATand ZATin' identically the same manner as in Fig. 1, and it is thought unnecessary torepeat the olescripti'on." When the relay lA'I is deenergized, the'lin'e wire Com is' connected with the C termiml of the'bat'tery 20 over a back 'contact'21 of ther'elay lAT, and when "that relay is picked up, this line wire is connected with "the B terminal 7 of the batterymj over' a front contact 22 of the 130 rel'ay l'AT It' i's clear,"tl'1"eref0re, that with the trackrelay 'ITRonIy released, the" relay" 1ATre mains deen'ergi'zed', and current of positive'' polarity' is" continuously suppliedl'tothe' line circuit. When the relayZTR isrel'ea'sed, the relay IAT is 135 picked up, andcurrnt of negative polarity is contihuously supplied tothe' line circuit, and" when both the trackre'laysare released, the relaylA T is'operatfed, and currents of positive and negative polarities are"altern'atelyisupplied to the line cir'-' 1'46 cuit. 'In each case the contacts 21 and 22 function' conjunction with the? contacts l5 and 1-8 to"polejchange"the'conne'cti'onof the battery 20 with'theline" wires: L 'and'Com. It is apparent that the apparatus of'Fi'g. 2 willfunction' in the M5 same manner asthe apparatus of Fig. 1 "described hereinb'efore, to indicateat the 'ofiice station the trafilc conditions of thesections IT and 2T.

Although Ihave herein shown and described onlytwo' forms orapparatus"embodyingmy i-rr 15% vention, it is understood that various changes and modifications may be madetherein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, two sections of railway track, a track circuit including a track relay for each section, a line circuit comprising two line wires extending from said track sections to an office station and provided with a source of direct current at the end adjacent said track sections, a first and a second relay located adjacent said track sections and both normally deenergized, circuit means for continuously energizing said first relay effective when a particular one of said track relays is shunted but not the other and including a back contact of said second relay, other circuit means for energizing said second relay effective when both of said track relays are shunted and including a front contact of said first relay; whereby said first relay is continuously energized. when said particular track relay is shunted, said first relay is alternately energized and deenergized when both track relays are shunted and remain continuously deenergized when said other track relay only is shunted, means effective to supply current of one polarity to the line circuit from said source including aback contact of said other track relay and a back contact of said first relay, means effective to supply current of the opposite polarity to the line circuit from said source including a front contact of said first relay; and indicating means located at the ofiice station connected with said line circuit selectively responsive to steady direct current of one polarity, steady direct current of opposite polarity and to direct current alternating in poiarity.

2. In combination, two sections of railway track, a track circuit including a track relay for each section, a line circuit comprising two line wires extending from said track sections to an omce station and provided with a source of direct currentat the end adjacent said track sections, a first and a second relay located adjacent said track sections and both normally deenergized, circuit means for continuously energizing said first relay efiective when a particular one of said track relays is shunted but not the other and including a back contact of said second relay, other circuit means for energizing said second relay effective when both of said track relays are shunted and including a front contact of said first relay; whereby said first relay is continuously energized when said particular track relay is shunted, said first relay is alternately energized and deenergized when both track relays are shunted and remain continuously deenergized when said other track relay only is shunted; means effective to supply current of one polarity to the line circuit from said source including a back contact of said other track relay and a back contact of said first relay, means efiective to supply current of the opposite polarity to the line circuit from said source including a front contact or" said first relay; a first and a second loop circuit connected with said line circuit at the ofiice station each including a winding and an asymmetric unit, said asymmetric units arranged that one passes current of one polarity and the other passes current of the opposite polarity and a first and a second indicator controlled by the windings of said first and second loop circuits respectively.

3. In combination, two sections of railway track, a track circuit including a track relay for each section, a line circuit comprising two line wires extending from said track sections to an ofiice station and provided with a source of direct current at the end adjacent said track sections, a first and a second relay located adjacent said track sections, and both normally deenergized, circuit means for continuously energizing said first relay effective when a particular one of said track relays is shunted but not the other and including a back contact of said second relay, other circuit means for energizing said second relay efiective when both of said track relays are shunted and including a front contact of said first relay; whereby said first relay is continuously energized When said particular track relay is shunted, said first relay is alternately energized and deenergized when both track relays are shunted and remain continuously deenergized when said other track relay only is shunted; means efiective to supply current of one polarity to the line circuit from said source including a back contact of said other track relay and a back contact of said first relay, means effective to supply current of the opposite polarity to the line circuit from said source including a front contact of said first relay, a first and a second winding located at the ofiice station and connected with said line circuit, a bridge rectifier interposed between said windings and said line wires of the line circuit; said rectifier arranged in such a manner that a first arm passes current of one polarity to the first winding, a second arm passes current of the opposite polarity to the second winding, a third arm snubs the first winding to provide the winding with a slow-release period and the fourth arm snubs the second winding to provide that Winding with a slow-release period; and a first and a second indicator controlled by said windings.

4. In combination, two sections of railway track, a track circuit including a track relay for each section, a line circuit comprising two line wires extending from said track sections to an office station and provided with a source of direct current at the end adjacent said track sections, a relay located adjacent said track sections and normally deenergized, circuit means for continuously energizing said relay in response to a train occupying a particular one of said sections and including a back contact of the track relay of that section, other circuit means operating to alternately energize and deenergize said relay in re-- sponse to both sections being occupied and including a back contact of each of said track relays, means effective to supply current of one polarity to the line circuit from said source including a back contact of the other of said track relays and a back contact of said relay, means efiective to supply current of the opposite polarity to the line circuit from said source including a front contact of said relay; and indicating means located at the ofiice station connected with said line circuit selectively responsive to steady direct current of one polarity, steady direct current of the opposite polarity and to direct current alternating in polarity.

5. In combination, two sections of railway track, a track circuit including a track relay for 4'.

each section, a line circuit comprising two line wires extending from said track sections to an ofiice station and provided with a source of direct current at the end adjacent said track sections, a relay located adjacent said track sections and normally deenergized, circuit meansfor continuously energizing said relay in response to a train occupying a particular one ofsaidsections and including a back contact of the track relay of 5 that section, other circuit means responsive to both track sections being occupied and including a back contact of each of said track relays and effective to operate said relay to alternately close a front and a back contact of said relay for substantially equal periods, means effective to energize the line circuit with current of one polarity from said source and including a back contact of the other of said track relays and said back contact of said relay, means effectiveto energize the line circuit with current of the opposite polarity from said source and including said front contact of said relay; and indicating means located at the ofiice station connected with said line circuit selectively responsive to steady direct current of one polarity, steady direct current of the opposite polarity and to direct current alternating in polarity.

6. In combination, two sections of railway track, a track circuit including a track relay for each section, a line circuit comprising two line wires extending from said track sections to an office station; a battery located adjacent said sections provided with a positive terminal B, a negative terminal N and a central terminal C; a relay located adjacent said track sections and normally deenergized, circuit means for connecting the winding of said relay across the B and C terminals of said battery and including a back contact of a particular one of the track relays and operative .35: to steadily energize said relay in response to a train occupying the associated section, other circuit means for connecting the winding of said relay across the B and C terminals of the battery including a back contact of each of said track relays and operative to alternatelyenergize.and deenergize saidrelay in response to both track sections being occupied, means to connect one of said line wires with the C battery terminal, means to connect the other line wire with thev B battery terminal including a back contact of said relay and a back contact of the other of said track relay, means to connect said other line wire with the N battery terminal including a front contact of said relay; and indicating means located at the office station connected with said line'wires selectively responsive to steady direct current of positive polarity, steady direct current or negative polarity and to direct current alternately positive and negative in polarity.

7. In combination, two sections of railway track, a track circuit including a track relay for eachsection, a first andsecond line, wire extending from said tracksections to, an oifice station, a battery located adjacent saidsections, a relay located adjacent said sections and normally deenergized, circuit means including a back contact of a particular one of said track relays for connecting the winding of said relay across the battery to steadily energize said relay in response to a train occupying the section associated with that track relay, other circuit means including a back contact of each of the track relays for connecting the winding of said relay across the battery and operative to alternately energize and deenergize said relay in response to both track sections being occupied, means to connect the first line wire with the positive terminal of the battery including a first back contact of said relay and a back contact of said other track relay, means to connect the second line wire with the negative terminal of the battery includinga second back contact of said relay, means to connect the first and second line wires with the negative and positive terminal of the battery respectively including a first and a second front contact of said relay respectively, and indicating means located at the oflicev station connected with the line wires selectively responsive to current of positiveor negative polarity or to current alternating in polarity.

8. In combination, two sections of railway track, a track circuit, including a track relay for each section/a line circuit comprising two line f wires extending from said track sections to an ofiice station and provided with a source of current at the end adjacent said track sections, a first and'a second winding located at the oflice station connected with said line circuit, a bridge rectifier interposed betweenssaid, windings and said line wires; said rectifier arranged insuch a manner that a first arm passes current of positive polarity to the first winding, a secondarm passes current of negative polaritytothesecond winding', athird arm snubscthe first winding to provide it with a slow-release period and the fourth arm snubs. the second winding to provide it with a slow-releaseperiod; a first and a second indicator controlled by said first and second. windings respectively; means for energizing said line circuit with current of positive polarity from said source including a back contact of a particular one of said track relays, means to energize the line circuit with' current of negative polarity including a back contact of the other track, relay, and means to energize. said line circuit alternately with currents of positive and negative'polarities including a back contact of each of said track relays.

' PAUL H. CRAGO. 

